U.S. patent number 5,123,737 [Application Number 07/608,909] was granted by the patent office on 1992-06-23 for device for determining the deviation of a target from a predetermined location.
This patent grant is currently assigned to Precitronic Gesellschaft fur Feinmechanik und Electronic mbH. Invention is credited to Kurt Eichweber.
United States Patent |
5,123,737 |
Eichweber |
June 23, 1992 |
**Please see images for:
( Certificate of Correction ) ** |
Device for determining the deviation of a target from a
predetermined location
Abstract
A device for determining the deviation of a target provided with
a retrorector from a predetermined location in three spatial
directions has a laser and a quadrant detector arranged next to it,
which can be displaced jointly in the three spatial directions X,
Y, Z. In this arrangement, the Z-setting is readjusted with the aid
of a range measurement, so that the target is optimally
illuminated. On the basis of the signal in the quadrant detector a
displacement in the X-direction and Y-direction is effected in
order to obtain a zero signal from the quadrant detector. The
readjustments in the three directions are a measure of the
deviation which can be displayed on a display via control
electronics.
Inventors: |
Eichweber; Kurt (Hamburg,
DE) |
Assignee: |
Precitronic Gesellschaft fur
Feinmechanik und Electronic mbH (Hamburg, DE)
|
Family
ID: |
8202165 |
Appl.
No.: |
07/608,909 |
Filed: |
November 5, 1990 |
Foreign Application Priority Data
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Nov 27, 1989 [EP] |
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89121852.1 |
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Current U.S.
Class: |
356/152.3;
89/41.06 |
Current CPC
Class: |
G01S
17/42 (20130101); G01S 7/4812 (20130101) |
Current International
Class: |
G01S
17/42 (20060101); G01S 7/481 (20060101); G01S
17/00 (20060101); G01B 011/26 (); F41G
001/32 () |
Field of
Search: |
;356/141,152
;89/41.06 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0218178 |
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Apr 1987 |
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EP |
|
0246354 |
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Nov 1987 |
|
EP |
|
0253017 |
|
Jan 1988 |
|
EP |
|
1811540 |
|
Aug 1970 |
|
DE |
|
2850743 |
|
May 1980 |
|
DE |
|
2293714 |
|
Feb 1976 |
|
FR |
|
8501787 |
|
Apr 1989 |
|
FR |
|
1180778 |
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Feb 1970 |
|
GB |
|
Primary Examiner: Buczinski; Stephen C.
Attorney, Agent or Firm: Hayes & Reinsmith
Claims
I claim:
1. A device for measuring deviation from a predetermined location
in three spatial directions of a target provided with a
retroreflector, the device comprising a laser, a position-sensitive
detector adjacent the laser, a common element within which the
laser and detector are arranged, optical imaging devices for
directing a beam from the laser onto the retroreflector and for
imaging reflected light onto the position-sensitive detector, and a
laser range measuring device, the common element being arranged for
common linear displacement in said three spatial directions, the
common element having a power source and control means for tracking
the common element in a laser beam direction to a position which
corresponds to a measured range as determined by the laser range
measuring device and in directions perpendicular thereto a position
for which the position-sensitive detector transmits a zero
signal.
2. The device as claimed in claim 1, wherein the position-sensitive
detector is a quadrant detector.
3. The device as claimed in claim 1, wherein the laser range
measuring device is a traveltime range-finder.
4. The device as claimed in claim 2, including a beam splitter
positioned between the retroreflector and the quadrant
detector.
5. The device as claimed in one of claims 1 to 4, wherein optical
channels are provided for the emitted laser beam and the reflected
received light and are shielded from one another.
6. The device as claimed in one of claims 1 to 4, wherein optical
channels are provided for the emitted laser beam and the reflected
received light and are arranged next to one another.
7. The device as claimed in one of claims 1 to 4, wherein optical
channels are provided for the emitted laser beam and the reflected
received light and are arranged concentrically.
8. The device as claimed in claim 1, further including a halogen
search light directed to the target.
9. The device as claimed in claim 8, wherein the halogen search
light has an IR-filter with a swivel device.
10. The device as claimed in claim 1, further including a
television camera for imaging the target.
11. The device as claimed in claim 10, wherein the television
camera is a matrix-CCD camera.
12. The device as claimed in one of claims 1 to 4 or 8 to 11
further including a display device for hit position and range for
purposes of firing simulation.
Description
The invention relates to a device for determining the deviation of
a target provided with a retroreflector from a predetermined
location in three spatial directions, which has:
a laser and a position-sensitive detector arranged next to it,
which are arranged in a common element,
optical imaging devices for directing the laser beam onto the
retroreflector and for imaging the reflected light onto the
position-sensitive detector and,
a laser range measuring device.
As an example, but not exclusively, the device can be used for the
purposes of firing simulation. In general, the device can be used
for purposes in the case of which a direction and a range of a
target are set by other means, and it is then to be checked how
accurately the target has been set. For example, in this way the
device could serve surveying purposes.
The starting point in a known device of the type named in the
preamble of the new main claim (DE-A-3,404,496) is that the beams
falling onto the retro-reflector and the reflected beams are
parallel, the offset of these two beams being greater the less
centrally the retroreflector is hit by the impinging beam. The
offset zero then holds as the control criterion. The measuring
station with laser and position-sensitive receivers can be
swivelled about two axes H and V. Given appropriately long beam
paths, even a very small swivelling signifies a very large lateral
offset of the beam. It must therefore be ensured by means of
complicated mechanical devices that even extremely small
swivellings can be carried out. The device will therefore also be
very sensitive to disturbances, which can perhaps be accepted in
the of alignment with centimeter accuracy in tunnels or the like,
but not, for example, in the case of combat exercises with firing
simulation or in other cases where the devices are handled
relatively roughly.
By contrast, it is the object of the invention to create a device
with which the deviation of the set target location from the actual
target location can be measured simply and reliably.
The abovementioned previously known device operates with a
position-sensitive detector, which is composed of four individual
detectors. However, in this regard it is not a matter of what is
normally designated as a quadrant detector such as is known, for
example, from DE-A-2,850,743. In this previously known device, it
is not light reflected from a retroreflector that is measured but
scattered light. It is necessary once again to set two angles
accurately with respect to one another, by setting the laser and
telescope axes parallel. Thus, once again a swivelling movement
takes place with the required high accuracy and there is the need
to carry out the smallest swivelling movements exactly.
In the case of a device known from DE-A-1,811,540, it is, once
again, possible only to rotate and swivel. Thus, once again only
the angle is varied. It is also important in the case of the last
mentioned device that the incoming and outgoing beams have the same
finite spacing from one another, because of the finite magnitude of
the prism 3. This geometry does not, of course, occur if the triple
mirror is very far removed from the laser.
The abovementioned object is achieved when the common element is
arranged for common displacement in the three spatial directions
and when circuits are provided for tracking the common element in
the laser beam direction to a position which corresponds to the
measured range, and in the directions perpendicular thereto to a
position for which the position-sensitive detector transmits a zero
signal, it being possible to compute and display the deviation from
the magnitude of the tracking.
As has been said, only swivelling movements take place in the of
all three abovementioned devices. By contrast, in the case of the
device according to the invention a linear displacement takes place
in the three mutually perpendicular spatial directions, as a result
of which not only can the reflected light beam be accurately set to
the zero position of the position-sensitive receiver, but, in
addition, due to the movement in the Z-direction there is also a
sharp setting, something which is not to be gathered from the
patents cited.
When the target is set, for example in the case of firing
simulation, the device is correspondingly aligned, i.e. the common
element is set in the laser beam direction in accordance with the
set range, so that the laser beam is optimally focused onto the
target by the optical imaging device (usually a lens or a lens
system). The common element is likewise correspondingly aligned in
the directions perpendicular thereto.
If, now, the deviation is to be determined, the laser is switched
on by, for example, squeezing a trigger, in particular the trigger
of a firing simulator. In this case, the laser signal is sent to
the target, where it is reflected back from the retroreflector and
reaches the laser range measuring device via a beam splitter, on
the one hand. If the set range does not coincide with the range
determined in this way by a travel-time measurement, a readjustment
of the common element and thus of the laser and the quadrant
detector takes place in the Z-direction, i.e. in the laser beam
direction, so that the light spot has an optimum magnitude at the
location of the target. On the other hand, the reflected laser
light impinges on the quadrant detector. If, in this case, it does
not fall precisely on the intersection of the four quadrants, the
quadrant detector transmits signals, which are used for the purpose
of displacing the common element in such a way that the light spot
falls precisely on the center of the quadrant detector which then
transmits its zero signal. The displacement in the Z-direction for
setting the range, and the necessary displacements in the
directions perpendicular thereto (X-direction and Y-direction), for
the purpose of maintaining the zero signal of the quadrant
detector, are a measure of the deviation, which can be displayed on
a display after appropriate conversion.
Reference was made above to a travel-time range-finder because it
is especially expedient; however, it is also possible to use other
method of range measurement.
Again, the beam splitter before the quadrant detector is certainly
particularly advantageous; however, with other types of range
measurement such a splitter could be dispensed with.
It is expedient for the optical channels for the emitted laser beam
and the reflected received light to be shielded from one another so
that stray light cannot reach the quadrant detector directly from
the laser, which would reduce the sensitivity.
It is expedient for the two channels to be arranged next to one
another. However, they can also be arranged concentrically by
arranging concentrically around the lens that emits the laser light
an annular lens which concentrates the reflected light behind the
laser onto the quadrant detector.
It is expedient for the device additionally to have a halogen
search light, which in the case of a particularly advantageous
embodiment has an IR filter with a swivel device. The halogen
search light and/or the IR filter can then likewise be switched on
by means of the trigger or a pretrigger. It is expedient for the
device further to have a television camera, for which, for example,
the halogen search light can be used as an illuminating system, if
other light sources are not available.
It is expedient for the television camera to be a matrix-CCD
camera, since then the received signals can be evaluated
particularly well.
In the case of firing simulation, both the television picture of
the television camera and the display device for hit position and
range can be made visible not only to the trainee but also, in
particular, to an instructor, who is able, in this way, to shape
and monitor the training in a particularly effective fashion.
The invention is described below on the basis of advantageous
embodiments with reference to the attached drawings, wherein:
FIG. 1 shows a perspective view partly in section of an embodiment
of the device according to the invention;
FIG. 2 shows a top view of the quadrant detector which can be used
in the invention; and
FIG. 3 shows another type of the optical elements of the
device.
In the Figures, 1 indicates in general a device with which the
deviation of a target 2 can be determined. The target is provided
with a retroreflector 3, and can be displaced in the X, Y and
Z-directions, as is indicated by the corresponding arrows in FIG.
1.
The device 1 has a laser 4, whose emitted light 5 is focused by a
lens 6. The laser 4 is fastened to an element 7, which is a part of
a displacement mechanism that consists of the elements 7, 8 and
9.
The element 9 can be moved on a support 11 in the Z-direction, i.e.
in the laser beam direction, by means drive devices (schematically
shown) via and an energy or power source and control circuit 10.
Arranged on the element 9 is an element 8, which can likewise be
moved with the aid of the power source and control circuit 10, to
be precise relative to the element 9 and in the X-direction, i.e.
the horizontal direction. The element 7, in turn, can be moved
correspondingly in the vertical Y-direction relative to the element
8.
The light 12 reflected from the retroreflector 3 35 is focused by a
lens 13 and is, on the one hand, projected via a beam splitter in
the form of a semitransparent plate 14, onto a detector 15 which
serves the purpose of travel-time range measurement. On the other
hand, the light falls on a quadrant detector 16, which is likewise
fastened on the element 7 next to the laser 4. The detector 15 and
the quadrant detector 16 are connected to an evaluation circuit 17,
which, for the purpose of displacement, is connected in turn to the
power source and control circuit 10.
The device operates as follows.
After, for example, in firing simulation, the device has been aimed
at the target, a trigger 18 by which the laser 4 is switched on is
operated. The light 12 reflected from the target 2 or
retroreflector 3 falls on the detector 15. The range of the target
is then determined by a travel-time measurement with the aid of the
unit 17. If the position of the laser 4 in the Z-direction does not
correspond to the optimum angle of illumination at the target
location, a readjustment takes place in the Z-direction.
On the other hand, the reflected light spot falls on the quadrant
detector 16, as, is indicated at 26 in FIG. 2. Since the light spot
26 is not located at the center, a readjustment in the Y-direction
and X-direction takes place until the light spot is located at the
center of the quadrant detector, as is indicated by a dashed line.
The displacements in the Y-direction and the X-direction likewise
take place in this process via the electronic of evaluation circuit
17 and the control circuit and power unit 10.
If the correct positions have been set in the three directions, the
deviation can be determined in the unit 17 from the readjustment
carried out, and displayed in a monitor unit 19.
As is shown in FIG. 1, it is also further possible to provide at
the trigger 18 a pretrigger 20 by means of which it is possible for
a halogen lamp 21 to be switched on or, if the halogen lamp had
already been previously switched on, for an IR filter 22 to be
swivelled away from the lamp 21 with the aid of a swivelling
mechanism 23, so that the light reaches the target. The target
surroundings can then be imaged by means of a television camera 24,
in particular a matrix-CCD camera, and displayed on a monitor
25.
In FIG. 3, the channels for emitted laser light and received
reflected light are not arranged next to one another as in the
embodiment of FIG. 1, but are arranged concentrically with respect
to one anotehr. For this purpose, the lens 13 is arranged as an
annular lens concentrically around the lens 6. In this arrangement,
the lens 13 has a longer focal length, so that the light is focused
behind the laser 4 onto the detector 16. The laser 4 and detector
16 are, once again, jointly readjusted in the three spatial
directions by an adjusting device 7, 8, 9.
* * * * *